Sometimes things aren't black and white. But teacher/pupil and adult/under age seem pretty black and white to me!
And my understanding of peadophiliia is"attraction to children". Which she is. Therefore it makes him that. I think it is important to name him as such, as otherwise we get into this thing of "ahhhh, but she's not pre-pubescent so it's not too bad. Easy mistake to make" rubbish that does not excuse abuse.
Anyway, I rant about this stuff quite frequently. I might stop doing it online now.